1. Field of the Invention
The present invention relates to a lighting structure for a meter device mounted on a vehicle or the like.
2. Description of the Related Art
In such a meter device mounted on a vehicle or the like, a dial having characters, numeric characters and scales or the like provided is ordinarily lighted from a back surface side by a dedicated light source or a pointer which indicates the characters or the numeric characters on the dial is lighted (for instance, see Japanese Patent No. 3291732).
Namely, this meter device is an indicating meter useful as a speed meter of a motor vehicle. As shown in FIG. 14, a motor casing 102 is attached between a printed circuit board 101 and a dial 107. A rotating shaft 106 formed with a hollow shaft is supported by shaft support parts 104 and 105 of the motor casing 102. To the rotating shaft 106, a pointer shaft 110 formed integrally with a pointer 109 is attached. The pointer 109 is rotated by a motor provided in the motor casing 102 which is not shown in the drawing through the rotating shaft 106. Further, in the rotating shaft 106, an LED (Light Emitting Diode) 111 is arranged as a light source. The LED 111 is fixed to the printed circuit board 101 and outputs illuminating lights to a light receiving surface 109A of the pointer 109. The illuminating lights incident on the pointer 109 are reflected on a reflecting surface 109B to allow the pointer to emit the lights and illuminate the pointer 109. In this meter device, for illuminating the dial 107, dedicated light sources, which are not shown in the drawing, are separately arranged at a plurality of parts below the dial 107.
As such a meter device, a meter device is also known which is formed so as to improve a light emitting efficiency of a pointer (for instance, see JP-T-2009-537844).
As shown in FIG. 15, this meter device includes a motor casing 201, a pointer 202 guided through a protruding part 201A provided in a main body of the motor casing 201 and used as a bearing, a light source 205 formed with an LED spaced by a distance H from a lower end part 203A of a pointer shaft 203 provided in a base part of the pointer 202 and arranged just below a hollow shaft 204 and a printed circuit board 206 on which the light source 205 is mounted.
In this meter device, the pointer shaft 203 of the pointer 202 has a converging surface formed to be convex in the lower end part 203A in order to collect illuminating lights emitted by the light source 205 in an optimum way. The pointer 202 has the pointer shaft 203 of a cylindrical form and the lower end part 203A thereof preferably has a hemispherical form or a convex form, but, may have other forms than the above-described forms. In such a specific form, a focused state can be maintained so that the emission of the lights by the light source 205 is parallel to an axis of the pointer shaft 203. In this meter, a dial is lighted by arranging a plurality of dedicated light sources below the dial not shown in the drawing like the above-described meter device.